Sitting in the best bar in Jerusalem about four months ago (it’s called Sira, in case you’re interested), I entered into conversation with a tall, ginger-haired young man who turned out to be a member of the Swedish contingent in the Temporary International Presence in Hebron (TIPH). Our conversation ranged over the trials and tribulations of the life of a member of TIPH, the very large amounts of money he seemed to be making, and the merits of Jerusalem when compared with other cities in the region.

An offhand remark he made concerning the political balance of power in Hebron turned the conversation from mildly interesting to memorable. I asked him if Hamas was gaining ground in the city of Hebron. He replied wearily that the fastest-growing political force in the city was not Hamas, nor any of the other well-known Palestinian political movements. Rather, the most notable and noticeable development on the ground in Hebron was the sudden and rapid rise in support for the Islamist party Hizb ut-Tahrir.

Subsequent months have attested to the truth of my Swedish friend’s unexpected claim. Hizb ut-Tahrir (the “party of liberation”) is indeed growing in strength and visibility in the West Bank, especially in the areas of Jerusalem and Hebron. So what does the Hizb’s emergence as a political factor mean, and what implications may it have (if any) for the future direction of events between Israelis and Palestinians?

Hizb ut-Tahrir was founded in Jordanian-ruled Jerusalem in 1952 by a sharia court judge, Taqiuddin al-Nabhani. The party inscribes on its banner the goal of the restoration of the caliphate – the Islamic government established after the death of Muhammad in 632, and abolished by Kemal Ataturk in 1924.

The party wants the imposition of sharia law – eventually worldwide – and is in favour of the destruction of Israel. However, it sees this as the job of the conventional forces of the restored Islamic caliphate. The party has thus not employed the methods of terror attacks against Israelis, as favoured by other, more prominent Palestinian Islamist currents, such as Hamas and Islamic jihad.

Hizb ut-Tahrir has grown from its beginnings in Jordanian Jerusalem into an international force, with branches in 45 countries in the world. It has achieved particular notoriety in central and southeast Asian countries, in particular in Uzbekistan and Indonesia. It has also come to prominence in western European countries – particularly in Britain, where a branch was established in 1986. A number of the best-known British participants in Islamist terrorism attended meetings of the group or one of its offshoots at certain stages of their trajectories. These include Omar Khan Sharif, who tried to bomb the Mikes Place bar in Tel Aviv in 2003, and the “shoe bomber”, Richard Reid.

In the Arabic-speaking world, Hizb ut-Tahrir was long regarded as an obscure, eccentric current. Some analysts saw its failure to place the Palestinian issue at the centre of its concerns as contributing to its marginality. This is now changing. In the West Bank in the last months, Hizb ut-Tahrir has held a series of successful events, which mark its entry onto the stage as a significant player in Palestinian politics. In early August, the party organised a number of mass rallies in the West Bank, including a gathering of 10,000 people in the town of Al-Bireh, and similar-sized rallies in Hebron and Ramallah. These took place under the slogan “The caliphate is the rising force”, and coincided with similar gatherings held by branches around the world. The rallies followed a year of frenetic activity and growing prominence for the movement in the West Bank, which saw activists, for example, protesting against the establishment of a new mission school in Hebron in May, 2007 and organising demonstrations in protest at the Danish cartoons of Mohammed in October, 2006.

What does the rise of Hizb ut-Tahrir among Palestinians imply? First, it indicates that the assumption over the last two decades that Palestinian politics was essentially a two-horse race between nationalist Fatah and Muslim Brotherhood/Hamas may be beginning to fray at the seams.

More profoundly, the emergence of the movement raises a question over the optimistic scenario recently raised in some quarters, according to which once Islamist movements such as Hamas are tested in office and fail, previous, predominantly secular patterns of politics will re-emerge.

It may well be that a deep, and profoundly significant “Islamisation” of the politics of the Arab world is taking place, the implications of which are only beginning to be glimpsed. Looking around the region, the wall-to-wall dominance of Islamist groups in opposition politics appears to attest to such a process. Hizb ut-Tahrir itself may well end up being only one of many symptoms of this broader trend, all trying to ride the wave.

Such a shift, if it takes place, would have severe implications for hopes of a consensual peace between Israelis and Palestinians, and for wider regional stability. A Fatah official I spoke with recently told me that in his view Abu Mazen was “the last Palestinian,” whose failure would mean the emergence to prominence of a new brand of chaotic, rejectionist politics among the Palestinians.

So had my Swedish friend – enjoying his weekend off in a west Jerusalem bar – revealed a dot on the horizon, indicating the approach of something new? It’s too soon to tell, of course. But interested parties among both Israelis and Palestinians will no doubt be keeping a close eye on the activities of Hizb ut-Tahrir in the West Bank in the period to come.